Eco-efficiency analysis of products or processes

The Eco-efficiency analysis, used in this strategy, combines environmental impact with for example toxicity and economic costs to quantify the sustainability of products or processes from a life cycle perspective. The result expresses the ratio of creation of economic value to ecological impact of the products. The alternative that provides the specific customer benefit to lowest cost and environmental burden is the most eco-efficient. The analysis only provides comparative information and no absolute values, since all results are normalized in order to visualize the comparison of the products in resulting diagrams

Six different environmental impact categories are included in the analysis; 

• Raw material consumption 
• Energy consumption 
• Emissions to air, water and waste 
• Toxicity potential 
• Risk/ misuse potential 
• Area use 

Data acquisition and calculations are done according to ISO 140 40 standards for the categories raw material consumption, energy consumption and emissions. For the other categories, other ways to compile and assess data has been developed.

The procedure 
Below is a schematic model of the method.

Figure 1 Schematic model of Eco-efficiency analysis (From BASF)

The first step in the analysis is to define the customer benefit, which leads to a definition of functional unit. Alternative technologies are also defined during this process. As many competing products or processes as possible should be included. The ecological analysis starts out as a Life Cycle Inventory, done according to ISO 14040-14043. For each alternative, all input during the life cycle, such as raw materials and energy, and all output during the life cycle, such as emissions to air, water and wastes, is compiled and calculated.

The toxicity potential and risk potential are also assessed in this step. The toxicity potential is based on European risk phrases. When no classification with European Risk phrases for a substance is available, toxicologists carries out an assessment. For the analysis of risk potential possible hazards for all alternatives is defined and the likelihood and impact of each hazard is assessed.

Life Cycle Inventory 
The Eco-efficiency analysis includes a Life Cycle Inventory, LCI. The LCI is the first step in a Life Cycle Assessment, LCA, which is a common used tool to assess the potential environmental impacts of product systems or services. In an LCI all stages in the life cycle - from extraction of resources, through the production and use of the product to reuse, recycling or final disposal is included.

The data collection forms must be properly designed for optimal collection. Subsequently data are validated and related to the functional unit in order to allow the aggregation of results. A very sensitive step in this calculation process is the allocation of flows e.g. releases to air, water and land. Most of the existing technical systems yield more than one product. Therefore, materials and energy flows regarding the process as a whole, as well as environmental releases must often be allocated to the different products.

Weighting 
The environmental impact categories are combined via a weighting scheme to form a total value for environmental impact. This weighting scheme is made up of relevance factors and societal factors (see Figure 2). The weighted result is used to compare different alternatives.

Figure 2 Composition of the total weighting factors

First of all, the relevance and society factors need to be determined. The societal factors are based on public views and opinion polls on how important it is to avoid certain impact categories and they are adjusted to the geographical region, where the study is performed.

The relevance factors answers the question; how much does the product or process contribute to the total environmental impact in the geographical area? The relevance factor, also called scientific weighting factor, indicate how important the individual environmental impact categories of the product are to the total environmental impact in the reference area.

Costs 
In the cost analysis, the costs for the end customer are summarized. That means for example sales price, costs related to utilization of the product and costs related to end of life treatment. The sales price normally reflects production price. For durable goods the cash value method is used. In addition, costs for the individual life cycle segments for all alternatives can be compiled, to form the basis for the analysis.

Presentation of results 
The result of the analysis is presented in an eco-efficiency diagram that illustrates the normalized relationship between the different products. Cost and environmental impact form the two axis of the eco-efficiency diagram. The scale is inverted so products with lowest price and lowest environmental impact are found in the upper right corner.

Figure 3 The Eco-efficiency diagram shows the result of the eco-efficiency study

The greater the distance of the points from the diagonal towards top-right is, the higher the eco-efficiency of the alternatives. The diagram is easy to understand for people not involved in the study since the results in all categories have been normalized, weighted together and plotted as one point for each alternative in the diagram.

Results from the analysis of the Environmental impact are combined in an Ecological Fingerprint. Each environmental impact category is normalized, which means that the worst case in each category is assigned the value one and the others receive a value in relation to one. Example; if Product A has 50 kg emissions and product B has 40 kg emissions, Product A assigned 1 and Product is assigned 0,8. Each product is illustrated in the fingerprint with a line. Lines further to the central of the fingerprint have lower environmental load.

Figure 4 The Ecological fingerprint shows the result of the environmental impact

Experiences